This proposal describes several studies of speech production and speech perception to investigate the timing of phonetic events such as consonant constrictions and vowel durations in spoken language. In particular, the temporal acoustic cues for the linguistic feature of voicing (as illustrated in the contrast between the words rabid and rapid) are explored in a variety of contexts. In one type of experiment, utterances will be recorded from subjects reading lists of controlled words or sentences and durational measurements of phonetic segments will be made from sound spectrograms. In the second type, synthetic speech stimuli will be prepared in which various temporal intervals are maniuplated systematically and the resulting stimuli played to subjects for identification of the items as common English words or nonsense words. The results of this work will contribute to a better understanding of the role of linguistic factors that influence timing in speech production and perception.